POS1001 CURRENT SMOKING IS ASSOCIATED WITH LOWER RISK OF UVEITIS AND PERIPHERAL ARTHRITIS IN MALES WITH AXIAL SPONDYLOARTHRITIS
Authors: K. Marsh, J. Carty, P. Gallagher, S. Maguire, F. B. O’shea, G. Fitzgerald
Journal: Annals of the Rheumatic Diseases (2022)

Background The associations between smoking and extra-axial manifestations of axial spondyloarthritis (axSpA) are inadequately described. Previous observational studies have demonstrated smoking as protective against some but not other manifestations. However, the impact of sex on these associations is unknown. Objectives Using a large descriptive epidemiological dataset, we performed a sex-stratified analysis of the association between smoking status and extra-axial manifestations in axSpA. Methods This study was carried out within the framework of ASRI (Ankylosing Spondylitis Registry of Ireland), a descriptive epidemiological study of the axSpA population of Ireland. A standardised clinical assessment was performed on each patient, collecting demographic and clinical data. Smoking status was characterised as current, previous or never. The number of cigarettes per day, plus number of years smoking was also collected. Data on the following extra-axial manifestations was collected: arthritis, enthesitis, dactylitis, acute anterior uveitis (AAU), psoriasis (PsO), inflammatory bowel disease (IBD). Standardised measures of disease severity were also collected. Separate logistic regression models were used to define the association between extra-axial manifestations and smoking, controlling for potential confounders. SPSS was used for statistical analysis. Results Smoking data was available for 913 out of the 917 axSpA individuals with data in ASRI (mean age 46 (SD 13) years, disease duration 19 (SD 12) years, 72% male, 97% Caucasian). Twenty eight percent (n=259) were current smokers, 29% (n=268) were past smokers and 42% (n=386) were never smokers. Of the current smokers, the mean number of cigarettes per day was 12 (SD 7) and number of years smoking was 22 (SD 12). Thirty one percent had peripheral arthritis, 7% had dactylitis, 18% had enthesitis, 34% had AAU, 17% had psoriasis and 11% had IBD. Current smokers had a significantly lower prevalence of arthritis and uveitis than past or non-smokers (see Table 1). A sex-stratified analysis was performed. There was no association between smoking status and any extra-axial manifestation in females. However, current smoking was associated with lower prevalence of arthritis in males compared to past or non-smokers (22% v 36% v 42%, p=0.002). A similar pattern was seen for uveitis, where male current smokers had a lower prevalence than non-smokers (24% v 38%, p=0.01). In contrast, psoriasis was more prevalent in men who were current smokers compared to non-smokers (18% v 12%, p=0.01), with no difference seen in females. There was no association with number of cigarettes smoked or number of years smoking. Table 1. Association between smoking status and extra-axial manifestations in axSpA. AxSpA cohort Current smoker Past smoker Non-smoker Arthritis 30.9% 22.4% a 35.5% b 33.3% b Dactylitis 6.7% 5.5% a 6.7% a 7.4% a Enthesitis 18.1% 17.4% a 16.2% a 19.9% a Uveitis 34.3% 27.4% a 35.0% b 38.6% b Psoriasis 16.7% 18.5% a 19.3% a 13.8% a Inflammatory bowel disease 10.7% 9.9% a 13.2% a 9.5% a Different subscript letters denote significant (p&lt;0.05) differences between groups. Significant values highlighted in bold. There was no association between smoking status and disease severity by subjective or objective measures, either for the cohort as a whole or by sex. When compared to non- or ex-smokers and controlled for potential confounders including sex, age, biologic use, the association remained only between current smokers and lower risk of uveitis (OR 0.68, 95% CI 0.49 to 0.96) and arthritis (OR 0.62, 95% CI 0.43 to 0.88), in separate logistic regression models. The association between current smoking and increased prevalence of psoriasis in males did not remain significant once controlled for confounders (OR 1.10, 96% CI 0.73 to 1.65). Conclusion We demonstrated that current smoking is independently associated with a lower risk of uveitis and arthritis in males with axSpA, but not females. More research is needed to further investigate this paradoxical finding. Disclosure of Interests None declared